The present invention relates generally to combination squares.
A combination square is a well known instrument used by carpenters, mechanics, tool makers, artisans, handy men and the like, which has a body (also referred to as xe2x80x9cheadxe2x80x9d) that typically slides in a groove formed in a rule. The body may be locked in place at any point along the rule, generally by means of a screw. The body of the combination square is generally formed with smooth surfaces set at 90xc2x0 and 45xc2x0, for constructing or checking right angles and 45xc2x0 angles.
The combination square as known today, was first disclosed by Laroy Sunderland Starrett in U.S. Pat. No. 282,583 in 1883. The Starrett combination square has a bubble vial set in the body for leveling or plumbing surfaces. The body is locked in place by means of a thumbscrew.
Other types of pioneering combination squares include an adjustable square described in U.S. Pat. No. 715,703 to Starrett, a miter and try square of U.S. Pat. No. 1,213,578 to Christian Bodmer, and a pivoting combination square of U.S. Pat. No. 1,948,951 to Austin L. Stowell, both assigned to the Stanley Works Co., and another pivoting combination square of U.S. Pat. No. 1,525,813 to Edward P. King, assigned to the L. S. Starrett Co.
All of the above squares use a transverse rib or nib, advanced by a thumbscrew or similar mechanism, to clamp the body to the rule, and retracted to release the body from the rule. The rib abuts against the longitudinal groove of the rule, rather than on a flat surface thereof. It is well known that it is, at times, very annoying and/or difficult for a person to reinsert the transverse rib back into the longitudinal groove extending in the face of the conventional rule member, when the rule member is slipped entirely free from the body or head of the square. It is a nuisance even to adjust the position of the rule as the rule does not slide well once the rib has been released.
Attempts have been made in the prior art to overcome the transverse rib problem. Examples of patents that do away with such a rib/nib include U.S. Pat. No. 1,519,209 to J. W. Parker in 1925, U.S. Pat. No. 2,296,531 to R. T. McQueen in 1942, U.S. Pat. No. 2,448,440 to E. I. King in 1948, and the more recent U.S. Pat. No. 4,028,814 to Andrews in 1977. In all of these patents, the head of the combination square is clamped straight down against the face of the rule member by means of a thumbscrew.
However, other than innovations in pivoting and clamping straight down against the rule member itself, the basic design of Starrett has changed little over the years.
The present invention seeks to provide an improved combination square. In one preferred embodiment, the body of the combination square includes two opposing members, each having a plurality of straightedged surfaces. The opposing members define a recess for receiving therein a rule member. A clamping element clamps the opposing members together. The clamping element turns about a turning axis to apply a clamping force via the body on the rule member. In contrast to the prior art, the turning axis does not traverse the rule member. The clamping element preferably mates with a bubble vial housing. The combination square has other features, which are described more in detail hereinbelow.
There is thus provided in accordance with a preferred embodiment of the present invention a combination square including a body including two opposing members, each having a plurality of straightedged surfaces, and a clamping element adapted to clamp the opposing members together, the opposing members defining a recess therebetween for receiving therein a rule member.
In accordance with a preferred embodiment of the present invention the opposing members are generally mirror images of each other
Further in accordance with a preferred embodiment of the present invention the rule member has a longitudinal groove formed therein, wherein the opposing members clamp against the longitudinal groove.
Still further in accordance with a preferred embodiment of the present invention the opposing members include a fulcrum against which they pivot to release the rule member.
In accordance with a preferred embodiment of the present invention the clamping element is attachable to the body and rotatable about a turning axis so as to apply a clamping force via the body on the rule member, the turning axis not traversing the rule member.
Further in accordance with a preferred embodiment of the present invention a bubble vial housing is provided, which is adapted to be secured to the body, the bubble vial housing including a clamp-receiving portion, wherein the clamping element mates with the clamp-receiving portion.
Still further in accordance with a preferred embodiment of the present invention the body is formed with a plurality of notches, and the bubble vial housing is adapted to be secured in a first orientation in at least one of the notches, and to be secured in a second orientation, rotated with respect to the first orientation, in at least one of another of the notches. The notches are preferably arranged such that the vial is parallel to the straightedged surfaces.
Each of the straightedged surfaces is preferably adapted to have a rule member pass therethrough. In one embodiment, a plurality of the rule members pass through at least one of the straightedged surfaces at one time.
In accordance with a preferred embodiment of the present invention some of the plurality of straightedged surfaces are angled with respect to each other at 45xc2x0 and 90xc2x0, and at least one additional straightedged surface is angled with respect to the other straightedged surfaces at an angle different from 45xc2x0 and 90xc2x0.